They update standards each year or make changes to previous standards...the recommended standards and practices for electrosurgery has not changed this portion of the recommendations. The principals of adipose tissue (as opposed to a muscle mass) creating impedance (with only fat to place a bovie pad on it is not as good as a muscle mass, and therefore you have to use two pads (close together, not on different parts of the body)) to lessen the impedance. If the muscle mass is covered by fat you don't get a good "path" for the return to flow back to the ESU. Two pads decrease the impedance...interestingly, even a small person may need two pads depending on the distribution of fat on their body, also two pads should be used in cases where you might use a high bovie setting. So glad I researched this! I may not be able to explain it the best but at least I know I have verification on this.